CN112074218A

CN112074218A - Paper towel

Info

Publication number: CN112074218A
Application number: CN201980029751.7A
Authority: CN
Inventors: 高桥祥子; 堀切川一男; 山口健; 柴田圭
Original assignee: Tohoku University NUC; Daio Paper Corp
Current assignee: Tohoku University NUC; Daio Paper Corp
Priority date: 2018-06-04
Filing date: 2019-06-03
Publication date: 2020-12-11
Also published as: EP3804592A4; WO2019235416A1; EP3804592B1; JP7121947B2; EP3804592A1; US20210198850A1; JP2019208846A; US11384483B2

Abstract

The invention provides a non-moisturizing high-grade tissue with excellent soft feeling. The problem is solved by a paper towel which is 2-layer paper towel without polyol external coating, wherein the basis weight of each layer is 14.0-17.0 g/m²The 2-layer paper has a paper thickness of 160-220 μm, a water content of 4.0-9.0 mass%, and contains 0.15-0.45 mass% of an oil component extracted with diethyl ether, and has a transverse bending rigidity of less than 0.006gf cm/cm and a transverse bending resilience of less than 0.005gf cm/cm.

Description

Paper towel

Technical Field

The present invention relates to a paper towel, and particularly to a non-moisturizing paper towel which is not externally coated with a polyhydric alcohol such as glycerin.

Background

The paper towels are roughly classified into a moisturizing paper towel in which a base paper is coated with a polyhydric alcohol having moisture absorption such as glycerin, and a non-moisturizing paper towel in which no polyhydric alcohol is externally coated.

Further, in the non-moist tissue which was not additionally coated with the polyol, the basis weight per 1 sheet was 12g/m²In addition to the so-called general-purpose, general-purpose tissue products, which place importance on price, the basis weight is as high as 14.0g/m²The above, high-priced, product group referred to as premium products.

The latter products with a high basis weight are regarded as high-grade products as compared with the general-purpose ones, and have advantages such as less stickiness due to polyhydric alcohol, dry feeling in use, and less possibility of transferring a drug to the skin.

Conventionally, paper towels belonging to such a product group have a high basis weight and a large thickness, and in order to exhibit a soft feeling and a smooth feeling as a high-grade product, a bulky agent has been used to reduce the density of the paper, and particularly to exhibit cushioning properties in the thickness direction.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2017-113223

Disclosure of Invention

Problems to be solved by the invention

However, it is difficult to further improve the soft feeling by merely reducing the density of the paper and improving the cushioning property in the thickness direction. Further, when the moisture content is increased like a moisturizing tissue, although a soft feel is easily expressed, when the moisture content is increased, it may be difficult to express the advantages of dry feel and excellent soft feel peculiar to a non-moisturizing high-grade tissue.

Accordingly, a main object of the present invention is to provide a soft touch sheet excellent in smoothness and having a basis weight per layer of 14.0g/m²The above high basis weight non-moisturizing tissue.

Means for solving the problems

A first means for solving the above problems is a tissue having 2 plies without applying a polyol coating thereto,

the basis weight of each layer is 14.0-17.0 g/m²，

The thickness of the 2 layers is 160-220 μm,

a water content of 4.0 to 9.0 mass%,

contains 0.15 to 0.45 mass% of an oily component extracted with diethyl ether,

the transverse bending rigidity is less than 0.006gf cm/cm, and the transverse bending resilience is less than 0.005gf cm/cm.

The second means relates to the tissue of the first means described above, wherein,

the longitudinal dry tensile strength is 200 to 350cN,

the transverse dry tensile strength is 50-90 cN.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention provides a soft touch excellent in smoothness and a basis weight per layer of 14.0g/m²The above high basis weight non-moisturizing tissue.

Drawings

FIG. 1 is a graph showing the results of sensory evaluation of examples of the present invention, comparative examples and conventional examples.

Detailed Description

Embodiments of the present invention will be described below. The tissue of the present invention is a polyol uncoated tissue to which no polyol is externally added by coating or the like. At least glycerin, 1, 3-butanediol, propylene glycol, 3-methyl-1, 3-butanediol, 1, 3-propanediol, and 2-methyl-1, 3-propanediol are the polyhydric alcohols according to the present invention, and the paper towel of the present invention is not externally coated with these substances.

In addition, the paper towel of the present invention has 2 layers, each of which has a basis weight of 14.0g/m²The above product category with basis weight higher than that of the product called general type, especially the range of the basis weight is 14.0-17.0 g/m²The range of (1). Basis weight of less than 14.0g/m²In this case, the thickness and bulkiness are difficult to be expressed. Therefore, it is difficult to feel the difference from the low-priced general purpose article. The basis weight is preferably 14.5g/m²The above. The higher the upper limit of the basis weight, the more excellent the thickness feeling, but the too high basis weight makes it difficult to express the soft feeling, so 17.0g/m²Less than, more preferably 16.5g/m²The following. The paper thickness is 160-220 μm in terms of 2 layers. In the above basis weight range, the density is low and cushioning properties are felt.

The basis weight in the present invention is a value measured in accordance with JIS P8124 (1998), and the paper thickness is a value measured under the same conditions using a dial gauge (thickness gauge) "PEACOCK G type" (manufactured by kazaki corporation) after sufficiently conditioning a test piece under JIS P8111 (1998). The specific procedure for the caliper measurement is as follows: after confirming that there is no dirt, dust, or the like between the plunger and the measuring table, the plunger is lowered onto the measuring table, the scale of the dial thickness gauge is moved to zero, the plunger is lifted up to place the sample on the test table, the plunger is lowered slowly, and the number of meters at that time is read. At this time, only the plunger is mounted. The terminal of the plunger was made of metal, and a circular flat surface having a diameter of 10mm was brought into contact with a paper plane perpendicularly, and the load during the measurement of the paper thickness was about 70 gf. The average value obtained by 10 measurements was used.

On the other hand, the tissue of the present invention is superior to the existing products in the above-mentioned range of basis weight and paper thickness, in other words, in the non-moisturizing high-grade tissue.

The paper towel of the present invention is characterized by containing 0.15 to 0.45 mass% of an oily component extracted with diethyl ether. Preferably, the content is 0.20 to 0.35 mass%. Diethyl ether is effective for extracting oils and fats as low-polarity substances. The pulp as a main raw material of the paper towel does not contain an oily component. Therefore, the oil component of the present invention is contained in the paper towel due to the internal additive. Note that, as the paper towel containing an oil component, there is also a paper towel to which an oil component such as silicone or polysiloxane is applied by external addition, but the above range is a range in which uniform application by external addition is difficult and an effect is difficult to be exhibited by external application. The present inventors have found that the oil component is contained in an amount of 0.15 to 0.45 mass% in a range not found in conventional non-moist tissue paper in both low basis weight general-purpose types and high basis weight high-grade types. When the content of the oily component is less than 0.15% by mass, the effect of improving the soft feeling and the smooth feeling is small; if the content exceeds 0.45 mass%, the cost is high and the production is difficult.

In the paper towel of the present invention, the amount of oily components extracted with diethyl ether is large due to the internal additive. That is, the oily component coating the pulp fiber surface is large, and the film of the oily component strongly acts on the surface smoothness and the function of weakening hydrogen bonds between pulps, and highly exhibits a soft feeling. Further, since the oil component coating the surface of the pulp fiber is large, the water content of the pulp can be maintained by the softener effect. That is, although the oily component itself does not have a moisture absorption effect, it does not interfere with the effect of the pulp fiber itself to retain moisture absorbed, and does not excessively reduce the moist feeling.

Here, in order to increase the content of the oily component, the amount of the softening agent containing an oil component may be increased, or the oil component in the softening agent may be increased, but since the oil extracted with diethyl ether is a low polarity substance, it is generally difficult to increase the fixation rate on the fiber even if the amount of the softening agent added is simply increased. In addition, the sticking rate (adhesion rate) to the dryer may decrease, and the workability may deteriorate. Therefore, in order to increase the fixation rate of the grease extracted with diethyl ether on the fibers, the chance of contact between the pulp and the grease can be increased. For example, a weakly cationic acidic softener containing a nonionic surfactant and a cationic surfactant may be dispersed at an appropriate position of a paper making apparatus such as a machine chest or a headbox (seed box) at a low concentration of 25 to 35 mass% as an active ingredient and a viscosity of 500mPa · s or less, and supplied to a paper slurry.

The amount of the softening agent is adjusted according to the type of the softening agent, and is about 0.2 to 0.5 mass% relative to the total weight of the pulp fibers. If less than 0.2 mass%, a sufficient softening effect may not be obtained; even if it exceeds 0.5 mass%, the fixation ratio may not be increased.

The kind of the softening agent is not necessarily limited, and as described above, a combination of a cationic surfactant and a nonionic surfactant is preferable. Softening agents such as higher alcohols, fatty acid esters, and acylamino acid esters may be added as long as the effects of the present invention are not impaired. In addition, a small amount of a humectant or the like may be added within a range not to impair the action and effect of the present invention, but the external polyol is not included.

Specific examples of the emollient component include avocado oil, almond oil, olive oil, camellia oil, sesame oil, rice bran oil, safflower oil, soybean oil, corn oil, rapeseed oil, almond oil, peach kernel oil, castor oil, sunflower seed oil, grape seed oil, cottonseed oil, coconut oil, wheat germ oil, rice germ oil, evening primrose oil, hybrid sunflower seed oil, macadamia nut oil, meadowfoam seed oil, hazelnut oil, palm kernel oil, palm oil, cocoa butter, shea butter, wood wax, mink oil, turtle oil, egg butter, beef tallow, milk fat, lard, horse oil, jojoba oil (jojoba oil), carnauba wax, candelilla wax, rice bran wax, western stomach oil, beeswax, shellac, lanolin, montan, paraffin, squalene, squalane, liquid paraffin, squash, microcrystalline wax, vaseline, soft isoparaffin, paraffin, and soft isoparaffin, Hydrogenated polyisobutene, ozokerite, mineral wax, alpha-olefin oligomer, polybutene, polyethylene and other hydrocarbons, or lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, hydroxystearic acid, oleic acid, linoleic acid, ethylhexanoic acid, isostearic acid, isopalmitic acid, isotridecanoic acid, isononanoic acid, pentadecanoic acid, lauryl alcohol, stearyl alcohol, cetostearyl alcohol, behenyl alcohol, cetyl alcohol, oleyl alcohol, lanolin alcohol, cholesterol, isocholesterol, sitosterol, stigmasterol, isostearyl alcohol, octyldodecanol, hexyldecanol, isopropyl myristate, isopropyl palmitate, butyl stearate, ethyl oleate, cetyl palmitate, myristyl myristate, octyldodecyl oleate, cholesteryl stearate, cholesteryl hydroxystearate, glyceryl tricaprylate, glyceryl trimyristate, etc, Glyceryl triisooctanoate, isopropyl isostearate, ethyl isostearate, cetyl ethylhexanoate, stearyl ethylhexanoate, glyceryl triethylhexanoate, trimethylolpropane triethylhexanoate, pentaerythritol tetraethylhexanoate, glyceryl triisostearate, trimethylolpropane triisostearate, pentaerythritol tetraisostearate, pentaerythritol triisostearate, isocetyl isostearate, octyl dodecyl dimethyl octanoate, myristyl lactate, cetyl lactate, trioctyl dodecyl citrate, and diisostearyl malate. These may be used singly or in combination of two or more.

The cationic surfactant may be appropriately selected from quaternary ammonium salts, amine salts, amines, and the like. Particularly suitable cationic surfactants are quaternary ammonium salts, which are preferably used. Specific examples thereof include dilauryldimethylammonium chloride, distearyldimethylammonium chloride, dimyristyldimethylammonium chloride, dipalmityldimethylammonium chloride, and distearyldimethylammonium chloride.

As the nonionic surfactant, ester type, ether type, ester ether type, alkanolamide type, alkyl glycoside, and the like can be used. Examples of the ester type include sorbitan fatty acid ester, diethylene glycol monostearate, diethylene glycol monooleate, glycerol monostearate, glycerol monooleate, propylene glycol monostearate, N- (3-oleoyloxy-2-hydroxypropyl) diethanolamine, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan beeswax, polyoxyethylene sorbitan sesquistearate, polyoxyethylene monooleate, and polyoxyethylene monolaurate. Further, the ether type includes polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, and the like, and specific examples thereof include polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, and the like.

Here, the ratio of the oily component extracted with diethyl ether in the present invention is a value measured by a quick residue extraction apparatus OC-1 manufactured by Intec corporation or a machine or an exchange machine thereof. The device has the following structure: adding a sample into a subsidiary test tube having an extraction port at the lower part thereof and supplying a solvent, wherein the extraction liquid is dropped from the extraction port into a heated aluminum receiving dish located at the lower part thereof, and only the solvent is evaporated; the mass of the extract was determined from the mass difference between the aluminum receiving dish before and after dropping of the extract, and the oily component in the sample was measured quickly and easily. The ratio of the extract can be calculated from the mass of the extract and the mass of the sample. In the present invention, the sample was a tissue set 2 consisting of 2 plies and 1 set, and the amount of diethyl ether used was 10 cc. Further, the pushing-in was started by the push rod 60 seconds after the diethyl ether was thrown in.

The paper towel of the present invention has a transverse bending stiffness of less than 0.006gf cm/cm and a transverse bending resilience of less than 0.005gf cm/cm. This range is 14.0g/m as the basis weight of each layer²The high basis weight non-moisturizing tissue above is low. The paper towel of the present invention contains a large amount of an oily component, and exhibits remarkable characteristics in physical properties relating to the paper strength in the transverse direction of the paper because the bonding between fibers is weak. The lateral bending stiffness and the lateral bending resilience are characteristics when the sample is bent at right angles to the moving direction of the sample, and the longitudinal bending stiffness and the longitudinal bending resilience are characteristics when the sample is bent parallel to the flow direction of the sample. The transverse bending stiffness and the transverse bending resilience are indices relating to bending in a direction orthogonal to the ridge line of the fold, and therefore, when the transverse bending stiffness and the transverse bending resilience are low, the paper towel is soft and is easily felt soft. The transverse bending stiffness and the transverse bending resilience of the present invention are values measured by a pure bending tester KES-FB2-a manufactured by Katotech corporation, a machine in which the test pieces are attached to each other, or a measuring instrument having an interchangeable function. In addition, in the measurement, a sample subjected to humidity adjustment for 3 hours or more in a constant temperature and humidity chamber at 23 ℃ and 50% was used, the size of the sample was set to 200 × 200mm, the number of measurements was set to N5, and the average value was used as the measurement value. The bending rigidity is considered to have a soft feeling and a rigid feeling which a person feels when an object is bentIn this connection, it is considered that the larger the value of the bending rigidity, the stiffer the value, and the smaller the value, the softer the value. The bending return force is considered to have a correlation with the return force (elasticity) that a person feels when the object is restored to its original shape after bending, and the larger the value, the lower the return force, and the smaller the return force, the better the return force.

The paper towel of the present invention preferably has a dry tensile strength of 200 to 300cN in the machine direction and a dry tensile strength of 50 to 90cN in the transverse direction. Particularly preferably, the transverse direction dry tensile strength is 55 to 85 cN. When the dry tensile strength in the machine direction is in the range of 200 to 300cN, the dry tensile strength is sufficient. On the other hand, when the dry tensile strength in the transverse direction is less than 50cN, the sheet is easily broken in use. If the average particle diameter is larger than 90cN, the effect of improving the soft feeling is hardly felt. The paper towel of the present invention has low dry tensile strength particularly in the cross direction. Since the machine direction dry tensile strength is the paper strength in the direction of the wrinkle stretch, the strength can be easily adjusted by the wrinkle. The crepe ratio of the tissue of the present invention is preferably 15 to 28% during production. On the other hand, since the transverse dry tensile strength is the paper strength in the direction perpendicular to the longitudinal direction in which the wrinkles extend, the influence of the bonding of the fibers is large, and the feeling of softness is influenced. The transverse dry tensile strength of the present invention is slightly lower than that of the conventional high-grade tissue, and it is considered that the transverse dry tensile strength is caused by the decrease in the hydrogen bonding between fibers because the proportion of the oily component extracted with diethyl ether is large. The tissue of the present invention is easy to feel soft by making the dry tensile strength in the machine direction a common range and making the dry tensile strength in the cross direction a little lower. The dry tensile strength of the present invention is a value measured by a tensile test according to JIS P8113 (1998). In the adjustment of the dry tensile strength of the present invention, a known dry strength agent can be used. Thus, the tissue of the present invention has a cross-machine direction dry tensile strength superior to that of the prior non-moisturizing high basis weight versions, more specifically a basis weight of 14.0g/m²The above non-moisturizing tissue is weak, and has a lower lateral bending rigidity and lateral bending resilience than the conventional non-moisturizing high-basis-weight high-grade tissue, and therefore has excellent softness and smoothness.

In another aspect, the tissue of the present invention is a non-moisturizing tissue. The water content thereof falls within a range of about 4.0 to 9.0 mass%, usually about 4.0 to 8.0 mass%. The moisture content as referred to herein is measured as follows. Two sets of samples were collected from the measurement subjects, and humidity was adjusted in a constant temperature and humidity chamber at 23 ℃ and 50% for 3 hours. Each sample was put into a weighing bottle, and the mass was measured after sealing. Then, the mixture was dried in a drier set at 105. + -. 3 ℃ for 4 hours in a state where the weighing bottle was opened. And (3) capping the weighing bottle in a drying machine, taking out the weighing bottle from the drying machine, naturally cooling the temperature to room temperature, and measuring the mass of the weighing bottle filled with the sample after further 15-20 minutes. Next, the moisture content was calculated from the formula of (moisture content (% by mass) — (((weight of the bottle + the sample before drying) - (weight of the bottle + the sample after drying))/((weight of the bottle + the paper before drying) - (weight of the bottle))) × 100. Here, when the difference between the moisture contents (% by mass) of the two samples is within 1.0% by mass, the average value thereof is used as the moisture content (% by mass) of the sample. The moisture content is expressed as% to 1-decimal place. On the other hand, when the difference between the moisture contents of the two sets of samples was more than 1.0 mass%, the test was performed again.

The tissue of the present invention is a non-moisturizing tissue, and has a moisture content in the range of 4.0 to 9.0 mass%. In the moist tissue, the moisture content is usually more than 10 mass%, which is significantly different from that of the non-moist tissue. Further, unlike the case of increasing the moisture content by externally adding a moisture-absorbing humectant like a moisture-retaining paper sheet, a dry feeling and a high-grade feeling with a thick feeling can be felt.

Here, as described above, the paper towel of the present invention does not contain glycerin as an external polyhydric alcohol, and further preferably does not contain glycerin as an internal additive. Glycerin increases the moisture content by high hygroscopicity, but a sticky feeling is exhibited when glycerin is contained. In addition, in other words, the present invention achieves a high moisture content and a content of oily components without including glycerin. Further, the tissue of the present invention preferably does not contain a polyhydric alcohol of a tertiary or higher order. They are oily components and exhibit a sticky feeling.

On the other hand, the pulp fiber in the tissue of the present invention is preferably obtained by blending NBKP (softwood kraft pulp) and LBKP (hardwood kraft pulp). In particular, the pulp fiber may be composed of only NBKP and LBKP, and the mixing ratio may be 20:80 to 80:20, and 30:70 to 60:40, in particular, NBKP and LBKP. The paper strength, softness, etc. can be adjusted by the compounding ratio of the NBKP to LBKP. The tissue of the present invention may contain known fibers such as chemical fibers, kenaf fibers, and cotton fibers within a range that does not impair the effects of the present invention.

[ examples ]

Next, physical property values were measured and a sensory test was performed for examples and comparative examples of the paper towel of the present invention. The compositions and physical properties of the examples are shown in table 1 below. The measurement method of each physical property value is as described above. Comparative examples 1 to 4 are high-grade commercially available products. In examples 1 and 2, as the softening agent, a weak cationic acid softening agent containing a nonionic active agent and a cationic active agent was used at a low concentration of 25 to 35 mass% as an active ingredient and at a viscosity of 500mPa · s or less to increase the fixation rate. The amount of the softening agent used was 0.32 mass% in example 1 and 0.38 mass% in example 2, based on the mass ratio of the pulp. The pulp fibers in examples 1 and 2 were 100% virgin pulp and did not contain old paper pulp.

In addition, sensory tests were evaluated as follows. The standard sample was comparative example 1. In comparative example 1, the advance evaluation of the soft feeling and the smooth feeling was high, and the amount of the oily component extracted with diethyl ether showed the highest value in the comparative example. The evaluation method was as follows: the evaluation of the standard sample was recorded as 4 points, and the samples of the other examples were compared with the evaluation of the standard sample and evaluated for 1 to 7 points. As rough criteria, the following criteria are given to the subjects: 1 minute: much worse (disliked) than the standard sample, 2 points: worse (disliked) than standard, 3 points: slightly worse (disliked) than the standard sample, 4 points: same as standard sample, 5 points: slightly better (liked) than the standard, 6 points: better (liked) than the standard, 7 points: much better (liked) than the standard.

For the evaluation of smoothness, 1 tissue set was folded in half in the longitudinal direction, the folded sample was placed on a horizontal table having a smooth surface, and the index finger was slid 1 time from one end to the other end in the lateral direction, to determine smoothness at that time. With respect to the evaluation of softness, moistness and liking, the subjects freely contacted 1 set of tissues to evaluate. The subjects were 11 persons, and the values in the table are the average values thereof. The results are plotted in fig. 1.

From the results shown in table 1, the amount of the extracted oily component in the examples of the present invention was 2 times or more higher than that of the commercially available product. That is, a large amount of oily components are contained. On the other hand, it is found that the moisture content is equivalent to that of the comparative example, and the moisture absorption property such as polyol is not exhibited. In particular, the physical property value of the transverse paper strength is low. The results of the sensory evaluation were very good not only compared with comparative example 4, which was a standard sample, but also compared with all other comparative examples.

Here, when the examples are compared with comparative example 2, comparative example 2 shows that the lateral bending resilience is equivalent to the examples, but the lateral bending rigidity is high. And the evaluation of soft feeling was low. That is, it can be said that when both the lateral bending resilience and the lateral bending rigidity are low, the soft feeling is significantly increased. In addition, when comparative example 3 and comparative example 4 were compared, the amount of the extracted oil component in comparative example 3 was larger than that in comparative example 4, but the result in sensory evaluation was poor. One reason for this is considered to be that comparative example 4 has lower dry tensile strength in the transverse direction than comparative example 3.

As described above, the present invention provides a soft touch sheet excellent in smoothness and having a basis weight per layer of 14.0 to 17.0g/m²High basis weight non-moisturizing tissue.

Claims

1. A paper towel having 2 layers without being coated with a polyhydric alcohol additive,

basis weight of each layer was 14.0g/m²～17.0g/m²，

The paper thickness of the 2 layers is 160-220 μm,

the water content is 4.0-9.0 mass%,

contains 0.15 to 0.45 mass% of an oily component extracted with diethyl ether,

2. The paper towel of claim 1, wherein,

the longitudinal dry tensile strength is 200 cN-350 cN,

the transverse dry tensile strength is 50cN to 90 cN.